Highly Efficient TiO₂-Based Microreactor for Photocatalytic Applications

Abstract

A photocatalytic, TiO2-based microreactor is designed and fabricated on a metal-titanium foil. The microchannel is mechanically engraved in the substrate foil, and a double-layered TiO2 anatase film is immobilized on its inner walls with a two-step synthesis, which included anodization and a hydrothermal treatment. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm the presence of an approximately 10-μm-thick layer of titania nanotubes and anatase nanoparticles. The SEM and transmission electron microscopy (TEM) of the cross sections show a dense interface between the titanium substrate and the TiO2 nanotubes. An additional layer of TiO2-anatase nanoparticles on the top of the film provides a large, photocatalytic surface area. The metal-titanium substrate with a functionalized serpentine channel is sealed with UV-transparent Plexiglas, and four 0.8-mW UV LEDs combined with a power controller on a small printed-circuit board are fixed over the substrate. The photocatalytic activity and the kinetic properties for the degradation of caffeine are provided, and the longer-term stability of the TiO2 film is evaluated. The results show that after 6 months of use and 3600 working cycles the microreactor still exhibits 60% of its initial efficiency.

Mussel‐Inspired Immobilization of Catalysts for Microchemical Applications

“…After the immobilization of TiO 2 nanoparticles, strong Ti O Ti stretching peaks for TiO 2 were clearly observed at 918 cm −1 ( Figure S4, Supporting Information). [ 28 ] XRD spectra of the TiO 2 -immobilized surface clearly revealed the characteristic scattering pattern of anatase TiO 2 , unlike a bare PDMS microchannel surface that presents only two diffraction halos at 5.6° and 11.7°, indicating the amorphous microstructure of PDMS ( Figure S5, Supporting Information). [ 29,30 ] From the above characterizations, it is clear that CA-PVP facilitates the immobilization of TiO 2 photocatalysts in addition to the control of spatial distribution TiO 2 photocatalysts and the microchannels of microreactors.…”

Photocatalytic activity of an electrophoretically deposited composite titanium dioxide membrane using carbon cloth as a conducting substrate

“…In the evaluation of the photocatalytic properties of the prepared materials, it was preliminary verified that the used compounds were stable in O 2 -saturated aqueous solution without any applied irradiation. 23 The presence of reaction intermediates was confirmed by HPLC chromatograms. It can be seen from the blank experiment performed on the bare carbon cloth, that all the target molecules, with the exception of uracil, are to some extent degraded in the absence of TiO 2 due to a limited photolysis 21 or to some photocatalytic activity of the bare carbon cloth.…”

Glass capillaries with TiO 2 supported on inner wall as microchannel reactors

“…Therefore, immobilized TiO 2 particles seem more attractive. However, systems with immobilized TiO 2 suffer from the limited amount of exposed catalytic surface area leading to mass transfer limitations [11][12][13].…”

“…Microreactors have proved to be highly effective for catalytic reactions due to its large surface to volume ratio, precise temperature and time control, and high production rate [12,14,15].…”